SUZUKA, Japan (Reuters) - World championship leader Nico Rosberg set the pace ahead of team-mate Lewis Hamilton as Mercedes dominated Friday's opening session of practice for the Japanese Grand Prix.

The German set the lead with one minute, 32.431 seconds, 0.215 seconds quicker than Hamilton, on a pleasant and sunny morning at the Suzuka circuit.

The Mercedes pair were a second clear of the Ferrari duo of Sebastian Vettel and Kimi Raikkonen who were third and fourth-fastest, respectively.

Vettel heads into the weekend carrying a three-place grid penalty for tipping Rosberg into a spin at the start of the last race in Malaysia.

Rosberg extended his lead over Hamilton to 23 points in the overall standings after the Briton was forced to retire from a comfortable lead in the Sepang race 16 laps from the finish.

As a result, Hamilton heads into Sunday's Japanese round desperately needing to revive his flagging title hopes with just five races remaining by clinching a third successive win at the Suzuka circuit.

Daniel Ricciardo, who inherited the win from Hamilton following his retirement in Malaysia was fifth fastest.

Red Bull team-mate Max Verstappen, who claimed second behind the Australian to secure the team's first one-two finish since the 2013 season-ending Brazilian Grand Prix, was sixth.

Force India, locked in a battle for fourth in the overall team standings with Williams, showed a strong initial turn of speed.

German Nico Hulkenberg was seventh-fastest for the Silverstone-based squad, ahead of Mexican team-mate Sergio Perez, who trialled the 'halo' cockpit protection device.

Fernando Alonso, hoping to impress on home soil for Honda, his McLaren team's engine supplier, was ninth.

The Spaniard survived an early collision with the barriers when his car snapped out of control on the entry to the fast Spoon corner and slid backwards into the tyre wall lining the track.